The Immortal Prophecies
by Scarlet Fairie
Summary: While stuck in the underworld, Percy made a deal with Chaos. Annabeth would be freed from Tartarus and sent back to camp. In exchange, he would be transported to an alternate dimension and never return. A place where swords transform into wands and gods into magic. The Wizarding World of Hogwarts.
1. Chapter 1

It was a dark, stormy night. Harry was walking in the woods with mist chilling him to the bones, even in his sleep. The fog swirled around his body and obscured the surrounding territory. The only thing the wizard could make out was the black shapes of trees in front of him.

Dreams like this had become quite common after the tri-wizard tournament, and the death of his godfather. Times when he was in complete darkness, unable to know where he was, and unable to find the light. It most likely had to do with his new-found knowledge that his destiny was intertwined with that of Voldemort. One way or another, someone would die in the end.

Harry resumed moving around in the surreal forest. He took small steps to prevent tripping, and to survey his trapped world. Visions could turn into nightmares at any second. He wanted to be prepared.

Suddenly, the black haired wizard sensed a presence behind him. He spun around to be greeted with... nothing. He frowned and took a step in the direction he was facing, still tense. Finally he relaxed as the feeling in his chest disappeared.

"Harry James Potter. How nice is it to finally meet you."

A deep, undescribable voice spoke directly into his mind. The power in it was overpowering and crippling to any kind of magic. Harry froze, his eyes widening in shock and terror. The sound was so familiar yet so grave that he was unable to formulate a proper response for a few seconds.

"Wh-who are you? What do you want?"

The Boy Who Lived was surprised at how his body stopped trembling after asking the questions. It was as if some of the pressure had been lifted off of his chest. Instead, he gazed straight ahead firmly, where shadows seemed to be gathering and almost taking the shape of a man. An immortal in human form.

"I do not hand out information lightly, _boy_. But for you, I will make an exeption because your future is very important."

Harry could tell that the unseen being was annoyed at haveing to give out any kind of explanation. It was never good to have darkness holding a personal grudge. He also was worried about the second part of the statement: his future. Sometimes, the Hogwarts student wished he was less vital in the wizarding wars.

"My name is Chaos. I am the creator of the universe, and I will be it's destroyer. I am here to deliver a prophecy."

The teenage wizard processed the information slowly. Chaos, the maker of the world, was visiting him in a dream. He was going to receive a prophecy. Was this actually happening? The immortal being interrupted Harry's thoughts as the voice resonated through his body.

"Now listen closely, for I will not repeat myself twice:

_There will come a green eyed knight,_

_Against the darkness he will fight,_

_No memory from a distant past,_

_His power is strong but will not last._

When you wake up, immediately write this down so you do not forget. Then go tell your headmaster. I will be waiting."

With those ominous last words the night seemed to break into dawn. Harry could not sense any presence other than his own. The primordial was gone.

He could feel his body twitching to awareness. Slowly, the gryfindor opened his eyes in the real world. He was laying on his bed in the 6th year rooms.

It took him a few seconds to realize what had just occurred. This vision he had was not the product of some new dish he had tried for dinner. He had been visited by a powerful being that knew of the future. He now has a message to deliver.

Harry stood on shaking legs and grabbed one of his black robes. He threw it over his nightclothes before silently sneaking out of the dorms. Chaos had told him to tell Dumbledore right away. This was what he had to do.

* * *

><p>Thousands of miles away, struggling through the pits of Tartarus, were two friends. A girl with long, matted blond hair and a boy with wounds covering his entire body. They stubbled along holding on to each other.<p>

They had a plan. Percy knew he needed to save Annabeth, to get them out of this hell. They would need to get to the Doors of Death to escape.

The truth was one of them would die. It was going to be him, he would stay behind and seal the doors. If they ever reached them, of course. Armys of monsters still stood between him and the outside world. A light gasp startled him out of his thoughts as the daughter of Athena hugged herself closer to him.

"Percy!"

He followed he gaze and froze in horror. In front of them, less an a hundred paces away, was a monster. No, it had to be a Titan. And a not very friendly one, if the evil glint in his eyes gave a clue.

"Annabeth, stay here. I'll handle this."

She reached a hand out towards him in protest. "No, you're injured."

However, he was already out of earshot. She felt tears come to her eyes as he rushed into battle. "Seaweed brain...don't you dare leave me."

Percy drew his sword from its sheath. He had found the blade somewhere in their travels that was made of Stygian iron. It was the only type of weapon that was suitable for using in the underworld.

With an exhausted shout, he sprinted forwards at his opponent. The titan was not a familiar face and the male demigod hoped that he was not extremely powerful. The son of Poseidon knew he would not be able to last in an extended battle.

As he swung his sword, the immortal simply stepped away from him and evaded the attacks. Percy ground his teeth and started to move fast in an attempt to hit the titan. However, he also became more careless.

The thousand years older being saw this and immediately took advantage of it. With one swift move he sidestepped Percy's attacks and knocked the demigod off his feet. He proceeded the pin down the the dark haired boy, and put his hands around his neck.

Percy struggled and pushed away from the titan, but was not strong enough. His vision started to blur as the air to his windpipe was cut off. Was this the end?

The hero of Olympus closed his eyes and prepared to open them again as a soul, waiting for Charon's boat. He silently prayed that Annabeth would be all right, even if it fell on deaf ears.

Well, maybe it didn't. Because right before he was about to black out, the pressure around his neck stopped. Percy opened his eyes and expected to see a large monster standing above him. Instead, he was alone in a white room with two doors. One was painted all black, while the other had a triangular symbol on it.

He dark haired boy furrowed his eyebrows. What was happening?

"Hello?" he called out uncertainly, not really expecting a response.

A deep chuckle made him flinch in surprise. "Hello Perseus Jackson. You must be very confused right now."

He did not protest the statement. It was true, after all. He should be dead right now. "What is happening? Where am I?"

"That does not matter, my young mortal." The voice continued in a slightly annoyed voice, "I am here because the fates have informed me that you have two options. One, you can die, simple and easy."

Percy winced. "And the other choice?"

"It would be much more challenging. You will live, but not in this world. If you choose this path, your female companion will be sent back to the surface of the earth. You will never return to her, or any other friends you have made." Now, the voice almost sounded amused, "Choose wisely."

He blinked. This was definitely not what he had expected, though it was not unwanted. He only had one true option. And if it meant loosing his memories and never seeing Grover or Chiron again, so be it.

"I want Annabeth to be free. Send me to this alternate universe of yours, whoever you are."

A rumbling sound filled the enclosed space. "Very well. Take the door on your right. And for future reference, my name is Chaos, the creator."

Percy choked in surprise and looked up to ask another question. This was _the_ real Chaos? However, a gust of wind blasted him towards the portal before he could say anything. His thoughts would be left unanswered because, at that moment, a white light flashed and blinded him as he tumbled onto... a marble floor.

The teenage boy groaned and rolled over on his back. Strange faces stared down at him, invading his personal space. That was before footsteps were heard and the young kids started to shift away from him.

"Give the boy some room," an older male voice commanded. Soon his face came into view.

The man had a long white beard and wrinkles on his face. He also was wearing an odd blue robe and cap. He towered above Percy and pursed his lips.

"Now, my son, who are you? And how did you get into my school?"

The confused demigod, who now possessed magical powers, was about to answer before-

"Wait! Look at his eyes!"

After the exclamation, everyone turned to stare at him. Most looked confused, and others amused. But near the back a gasp was heard from a dark haired boy with a scar.

_They're green._

* * *

><p><strong>AN: This is my first Percy Jackson/Harry Potter crossover. I hope everyone likes it. Please review!**


	2. Chapter 2

"W-where am I?"

Percy stuttered slightly, hoping the strange people around him would answer. He was extremely confused.

The man with silvery white hair signaled for him to stand. The former hero of Olympus quickly pushed himself off the ground and felt his legs tremble. Suddenly, he felt exhausted.

The same person who told him to get up was studying him with wise eyes. "You are in a wizarding school called Hogwarts. My name is Albus Dumbledore, I am the headmaster. Do you remember how you arrived here?"

Percy frowned, trying to think. He vaguely recollected fighting and being hurt, and a shadowy man talking to him, then suddenly being sprawled across the ground here. And something about blue chocolate chip cookies...But nothing more.

"I'm sorry, I don't remember."

"Hmm," the old headmaster stared down at the boy, pondering. "I do wonder who sent you here? But perhaps your memories will return with some food and rest."

Percy shifted his weight from foot to foot. As soon as a meal was mentioned, he realized he was actually starving.

Albus Dumble(something) started talking again, catching his attention. "Mr..."

"Jackson. Percy Jackson." He was surprised at how certain he was of that, but none of the other details in his past.

"Well, Mr. Jackson, why don't you go sit at a table and finish eating with some students. I'm sure _many _would be willing to explain wizard history and magic to you."

Immediately after this statement, a group of girls converged on him, all begging at once.

"Come sit at our table, Percy."

"There's an empty seat next to me."

"We can make new memories together."

He flinched, pulling away from the multitude of voices. From behind him, a hand landed on his shoulder lightly. It belonged to a black haired teen with a lightning bolt scratch on his forehead. "Hello. M'name is Harry. Would you like to sit with my friends and I at the table over there?"

Percy nodded gratefully, and followed his savior over to the long benches on the far left. He noticed a boy with ginger hair, and a girl with brown curls sit down next to them.

The redhead stuck out his hand. "I'm Ron."

"Nice to meet you," Percy mumbled, glancing at the last member of their group. She noticed his gaze and smirked.

"Hermione."

He nodded at both of them in acknowledgement. Then, he let his eyes trail over the buffet before him. Harry handed him a plate, "Have whatever you want. I recommend the treacle tarts for dessert."

The boy's emerald eyes widened in gratefulness. Everything looked amazing, he didn't know how he would choose. Finally the freckled kid, _Ron_, shoved a plater of mystery meat in front of him.

"Bloody hell, mate, just choose something already!"

Percy grinned. "I'm still not really sure if this is real," he mumbled while stabbing a piece of steak with his fork.

"Of course it is," Harry answered. "I can prove it to you, if you'd like."

The boy with glasses pulled out his wand without hearing his response. He then pointed at his own cup of pumpkin juice and whispered, "Wingardium Leviosa." Immediately, it started to levitate a couple inches off the table, catching some student's attention. He released the spell after a few seconds.

"So, do you believe now?"

Percy shook his head up and down, dumbfounded. "Is that a wand?"

Harry raised his eyebrows and struggled to refrain from laughing. "No it's a stick I found in the woods. Of course it's a wand, how else would I be able to use magic?" After a moments pause he added, "If you're a wizard, you must have one."

"I don't."

Hermione turned her body to face him, focusing on his front pocket. "Are you sure about that, Percy?"

He frowned and glanced down at his windbreaker. Speedily, he unzipped the pouch and slipped his hand inside. His expression changed as he felt a long, thin object in his palm. Wrapping his fingers around it, he pulled.

"No, look it's just a..._pen,_" he trailed off because the ballpoint marker he had felt just moments before had changed shapes. It was now made of a wood with small ridges.

He was holding a wand.

_His wand?_

Ron chucked from his seat on the other side of Hermione. "I guess you do have a wand. Do you really not remember anything?"

"I know my name and age, but that's about it," Percy shrugged. He took a sip of some unfamiliar drink before pointed to the emblem on their robes. "What's that?"

Hermione quickly started to explain, to his amusement. He could already tell she was a bit of a know-it-all. "It's the symbol of Hogwarts. The pictures on it are of the four houses: Gryfindor, Ravenclaw, Hufflepuff, and Slytherin. If you choose to stay at school, you will be sorted into one of them."

The green eyed boy nodded, the gears in his brain already turning. From what he could tell, Harry and his friends were gryfindors. But why? Did they possess similar qualities? And more importantly, where did he belong?

Hesitantly, Percy stopped eating so he was free to ask questions. Originally his trio of new friends were the only ones talking, but soon the whole table of boisterous and excited kids joined in. Because just maybe they saw something in him.

_The heart of a lion._

* * *

><p>That night, Percy slept in a side bedroom in the Central Tower. A professor had explained to him that it would be better not to sleep in one of the dorms, because he had not been sorted yet.<p>

They didn't want to cause unnecessary rivalry or animosity.

He wandered around the suite, letting his finders trail over the beautiful furniture and tapestry drapes. This place was exactly like a medieval castle. Even though he decided not to mention it, Percy was surprised at how quickly he was accepted and that the adults didn't ask him more question. Maybe it was just because he was disoriented.

He slowly walked back over to the bed and slid under the thick comforter. Harry had given him a pair of extra sleeping clothes, saying he could keep them. He would also have to buy robes and other supplies for classes quickly.

The softness of the mattress along with his exhaustion tempted him to close his eyes, and he drifted off to sleep.

Meanwhile, the wizarding staff were meeting in Dumbledore's office. The headmaster had called an emergency meeting after the events of that day. There, he informed everyone of the prophecy they had recieved a couple nights ago: a green eyed boy with magical power that would not last.

"Percy Jackson, though we do not know who he is or what he can do, will play an important part in the upcoming wars. We must keep a close eye on him."

They all agreed with him, this boy needed to be supervised very closely for at least the next couple days.

"Tomorrow, we will have his ceremony and then he will start classes with his schoolmates. We will act proceed as normal."

Professor Snape stood up, frowning. "But what if he is dangerous?"

Dumbledore thought for a second before answering. "If anything happens, bring him here to me." When no one started speaking he smiled. "Good, we are done here. Go back to your houses and take care of your own witches and wizards. DO NOT, do not mention this to anyone."

After his final words, the teachers all stood and filed out of his room, mumbling 'thank yous.' Soon he was alone in the chamber, only Fawkes and slivers of bright moonlight remaining. He stroked his beard pensively, lost in thought. This school year had just gotten a lot more complicated.

_Who are you, Percy Jackson? _

_Where have you come from?_

_And why are you so important that Chaos sent a prediction?_

Minutes past and Dumbledore sat down in his chair, drumming his fingers on his desk. There was only one thing his amnesiac new student could possibly do.

_Are you going to save our world?_

* * *

><p><strong>AN: Wow, I can't believe how many views, favorites, and follows this has gotten. Thanks so much! Please review. **


	3. Chapter 3

Percy bit his lip and stirred his cauldron desperately, attempting to stop the bubbling liquid from overflowing. Needless to say, he failed.

"Mr. Jackson. It seems you have the same ineptitude for potion-making as Mr. Longbottom."

The dark haired boy winced and glanced over at Neville, who was currently attempting to put out some flames that had erupted. With a wave of his wand, Professor Snape cleaned up the mess. Then he walked to to back of the classroom where he and Harry were working next to each other.

Raising his voice, the wizard reminded his students, "You will be turning in your final product at the end of the period for an assessment. It will count as part of your grade."

Why did the head of Slytherin house have to be such a..a..git! The older man almost seemed to hold a grudge against Percy for no particular reason. _Maybe because he was a Gryffindor? _

Immediately, he pushed the though out of his mind. The potionsmaster was not _so_ shallow that he'd treat Percy differently because of an age old rivalry. Though he didn't really understand magical politics. However, there currently was more pressing issues, such as the empty vial on the desk in front of him.

Quickly, the Boy Who Appeared From Nowhere (or so he had been dubbed by his growing fan base) picked up the glass vial and dipped it in the deep chestnut-colored mixture. It felt slushy, thick, sticky, and _very_ gross, and Percy yanked his hand out as fast as he could.

Next to him, Harry grinned. "It does feel pretty horrible, doesn't it? I guess that's what it takes to make a Draught of Despair."

"Even the name sounds ominous," the former demigod added.

The conversation was effectively cut off by the loud and monotonous voice of their teacher, announcing that work time was over. Percy grabbed his first ever potion made, and winced as he gave it to Professor Snape. He was pretty sure that, at least before he lost his memories, good grades did not come naturally. Learning about the Care of Magical Creatures was much easier than an elixir to induce euphoria.

But, the boy already felt a growing attachment to this strange new place and did not want to leave. And if that meant he was forced to study, he would study untill he had every single useless ingredient and mixture memorized.

"Percy! Hurry up!" A voice, Hermione's, startled him out of his distracted daze. His trio of new friends were waiting for him by the door impatiently. "We have Transfiguration - McGonagall. Don't want to be late."

He jogged over to his classmates. "Let's go then!"

The halls and moving staircases were still foreign to Percy. He had already managed to get lost once, and he didn't want that to happen again. One time was more than enough. He followed Hermione, Harry, and Ron closely as they walked through the dimly-lit castle.

After a few minutes, he let his mind wander away from the present and back to a couple days ago.

_"So you see, Percy, there have been as many magical wars as there's been muggle wars. Most recently, there was a dark wizard who despised muggles and muggleborns named Voldemort; though everyone calls him You-Know-Who (safety precaution). He was very powerful, and very evil. Thankfully, he died about sixteen years ago beacuse of Harry."_

Hermione never finished explaining how the glasses-wearing boy saved the world. He didn't understand how his new friend had killed an evil wizard at such a young age, but hopefully he would find out soon.

Though for the next hour, he would be learning how to turn a tea cup into a white dove. Wonderful.

Professor McGonogall did manage to make the class more interesting by giving incentives for the quickest students. Their houses would be rewarded 20 points. Which meant that the brown and thick haired Gryffindor girl would accomplish her task long before all of the other 5th years. Oh, the perks of having Hermione Granger in his class.

Percy was surprised when he complete the transformation on his third try. Harry clapped him on the back while Ron laughed at his gobblesmacked expression. "Hey, maybe you found your true talent."

Percy raised an eyebrow at that statement. "I highly doubt that."

At that moment, he accidentally waved his long oak and dragon heartstring wand. Sparks shot out of the tip, and the sleeves of his robe caught on fire. "AHH!" he shouted, waving his arms up and down to put out the blue flames. "I'M ON FIRE!"

The whole class turned to stare at him before bursting out laughing. Between fits of hysterics, Harry mumbled, "Maybe you need to read The Usage and Prevention of Accidental Magic. It might help in preventing any...problems."

Percy groaned in annoyance. "Shut up!"

* * *

><p>Chimes of forks and spooks against porcelain echoed throughout the Dining Hall. Chatter accompanied the noise in the huge chamber. The son of Poseidon sighed and rubbed his temples, trying to ease the headache. His robes were singed from earlier, he could barely keep his eyes open, and Professor Snape already disliked him. <em>This had been such a long day. <em>

But unfortunately it was not over yet. He still had one more class after dinner and, coincidentally, that was the one he was looking forwards to the most.

Defense Against the Dark Arts.

They would be learning powerful spells, spells that could beat evil. Having that kind of power... just the thought was exhilarating. There was only one small problem.

_"There is a rumor that the DADA position is cursed. No teacher has stayed for more than a year in a long time, whether they left or were killed. At least, not in a couple decades. It's probably the most dangerous job at Hogwarts."_

That meant that no one knew who would take over the class. Mentions of Snape, Dumbledore, and Mad-Eye Moody (or something like that) had been floating around. But, nothing was confirmed.

At least, not until right now. It was 6:50, ten minutes before the class commenced. Percy was sprinting through the walkways to the classroom, praying the whole time he was heading the right way.

Finally, he reached the heavy wooden doors. They were tall, almost eight feet, and had intricate carvings of lions, ravens, snakes, and badgers. Obviously for the separate houses. Waiting inside were Gryffindor and Slytherin students, ready for the period to start. To prepare himself, Percy took a deep and calming breath before entering.

Teenage witches and wizards were standing around and talking. The room was fairly empty, it only had tables and a blackboard in the corner. This was surprising, he had expected to see cages with monsters and books about the dark arts everywhere. But maybe those objects would be revealed later. Harry and Ron quickly waved him over to their desks, where a couple girls we sitting. As he approached, they giggled loudly. "Hi Percy."

"Hi Parvati. Hi Lavender."

The dark haired wizard slid into a chair next to his freckled friend. "So, where is our elusive new teacher?"

The Weasley brother shrugged. "Beats me. He should really be here by now or he's going to be late. Not a good first impression."

Harry leaned over to make a comment when a loud 'bang!' resonated in the thick marble walls. Smoke seemed to materialize and fill the room out of nowhere. When this happened, Percy started coughing and closed his eyes to prevent any damage. _What the heck is happening?_

Student's hacking and shallow breaths continued for a few more seconds until the steam thinned enough for visibility. In the centre of the area, which had previously been unoccupied, a tall and shadowed man was standing.

Percy squinted, unable to make out the stranger's full features. There was complete silence as students struggled to regain their bearings. Finally, a voice thundered

"What are you waiting for? Hurry up and get in your seats!"

When no one moved, the man sighed. "Now.."

Everyone shuffled reluctantly over to the desks, not wanting to anger the professor on the first day. Harry shook his head, a frown spread across his face. "I don't know why, but I think I recognize-"

"Please take out your books and have your wands ready." The wizard finally stepped out of the mist and murkiness, his mouth set in a firm line. He had short reddish brown hair and gentle eyes. Those eyes that almost seemed to stare into Percy's soul when they met his. Kind and warm but with a touch of brilliance. The Gryffindor felt an uncontrollable shiver go down his spine. _What was that about?_

A gasp from Harry made him jump slightly in surprise. "P-professor?"

The boy with the lightning scar stood and quickly rushed to the front of the classroom with long strides. He stood in front of the unfamiliar adult with an unreadable look on his handsome face. Then he did what Percy least expected; he hugged the man.

"Professor, you came back!"

* * *

><p><strong>AN: Here you go, chapter three. Sorry it took a while. So, who is their new teacher? If you want me to continue please favorite and follow. And review!**


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